CN107582081B

CN107582081B - Detection device and fatigue detection system

Info

Publication number: CN107582081B
Application number: CN201711045341.0A
Authority: CN
Inventors: 朱琳
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2017-10-31
Filing date: 2017-10-31
Publication date: 2020-01-10
Anticipated expiration: 2037-10-31
Also published as: CN107582081A; US20190125237A1; US10524717B2

Abstract

The invention discloses a detection device, comprising: a fixing member fixedly attached to a target position; at least one first electrode, one end of the first electrode is fixed on the fixed part, and the other end extends towards the first movable part along the first direction; a first movable member disposed opposite and parallel to the fixed member and movably connected to the fixed member by a first elastic member; and at least one second electrode, one end of which is fixed to the first movable part and the other end of which extends towards the fixed part along a second direction, wherein the second direction is parallel to the first direction. The invention also discloses a fatigue detection system. By the detection scheme, the acting force applied to the target position can be accurately detected, and the fatigue state of an operator can be detected.

Description

Detection device and fatigue detection system

Technical Field

The invention relates to a detection device and a fatigue detection system.

Background

The vehicle assistant driving system generally includes a road condition detection device, a vehicle condition detection device, and a driver state detection device, where the driver state detection device is used to detect various physiological parameters of the driver, such as sight direction detection, drowsiness detection, fatigue detection, and the like.

The fatigue detection comprises a detection device for detecting the grip strength, the temperature and the like of the steering wheel, the grip strength sensor determines the deformation of the elastic body through the detected capacitance change to detect the grip strength acting on the elastic body, and the detection device has the problems of low detection precision and requirements on the selection of materials of the elastic body.

Disclosure of Invention

In view of this, the embodiment of the invention provides a detection device and a fatigue detection system for improving detection accuracy.

The detection device provided by the embodiment of the invention comprises: a fixing member fixedly attached to a target position; at least one first electrode having one end fixed to the fixed member and the other end extending toward the first movable member in a first direction; the first movable part is arranged opposite to and parallel to the fixed part and movably connected to the fixed part through a first elastic part; and at least one second electrode, one end of which is fixed to the first movable part and the other end of which extends toward the fixed part along a second direction, the second direction being parallel to the first direction.

Preferably, the detection device further includes: a second movable member having at least one end fixed; at least one third electrode secured to the second movable element.

Preferably, the third electrode and the first electrode or the second electrode form a variable area capacitor.

Preferably, an insulating layer is provided between the third electrode and the first electrode or the second electrode.

Preferably, the third electrode and the first electrode form a variable pitch type capacitor.

Preferably, the second movable part extends in a third direction perpendicular to the first direction.

Preferably, the second elastic member is connected to each of both ends of the second movable member.

Preferably, the second movable part extends in a fourth direction parallel to the first direction.

The fatigue detection system provided by the embodiment of the invention comprises: any one of the above detection devices mounted on a vehicle steering wheel; a drive device that supplies an electrode drive signal to the detection device based on a predetermined drive instruction; and a processing device which calculates a force acting on the detection device based on the detection signal received from the detection device.

Preferably, the processing means is further configured to compare the calculated force to a predetermined threshold range, and the system further comprises: and a reminder device that issues a reminder signal when the processing device determines that the calculated force is outside a predetermined threshold range.

Preferably, the detection device further includes: a temperature sensor mounted on a side of the detection device away from the steering wheel or on the steering wheel adjacent the detection device; and/or a heart rate sensor mounted on a side of the detection device away from the steering wheel or on the steering wheel adjacent the detection device.

Through the detection scheme of the embodiment of the invention, the acting force acting on the detection device can be accurately detected, so that the current fatigue state of the operator can be accurately judged, and a better effect can be achieved in the aspect of fatigue detection.

Drawings

FIG. 1 is a schematic structural diagram of a detection apparatus according to an embodiment of the present invention;

FIG. 2 is a diagram illustrating a detection parameter calculation circuit for a detection apparatus according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a detecting device according to another embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a detecting device according to yet another embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a detecting device according to an embodiment of the present invention in one state;

FIG. 6 is a schematic view of the detecting device shown in FIG. 5 in another state;

FIG. 7 is a schematic cross-sectional view of a detecting device according to an embodiment of the present invention;

FIG. 8 is a schematic view of an arrangement of a detecting device applied to a steering wheel according to an embodiment of the present invention;

FIG. 9 is a schematic block diagram of a fatigue detection system of one embodiment of the present invention;

FIG. 10 is a schematic block diagram of a fatigue detection system in accordance with another embodiment of the present invention;

FIG. 11 is a schematic block diagram of a fatigue detection system in accordance with yet another embodiment of the present invention.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a detection apparatus according to an embodiment of the present invention.

As shown in fig. 1, the detecting device of the embodiment of the present invention includes a fixed member 10 and a first movable member 20 which are disposed opposite and in parallel, and a first elastic member 31 connected between the fixed member 10 and the first movable member. The first elastic member 31 may be a part or an entirety of a connection member connected between the fixed member 10 and the first movable member.

One side of the fixing member 10 is fixedly installed at a target position, which is a position where a force such as a pressure applied by an object or an operator needs to be detected, for example, a pressure place of an object to be detected, for example, a weight of the object to be measured, or an operation strength place to be detected, for example, a steering wheel of a vehicle.

One or more first electrodes 11 are disposed on the side of the fixed member 10 opposite to the mounting side, and the first electrodes 11 may be strip-shaped electrodes or columnar electrodes, one end of which is fixed to the fixed member 10 and the other end of which extends in a direction away from the fixed member 10, for example, may extend in a first direction perpendicular to the surface of the fixed member 10 toward the first movable member 20 opposite to the fixed member 10.

Both ends of the first movable part 20 may be connected to both ends of the fixed part 10 through the first elastic parts 31, respectively, and since the fixed part 10 is fixed at the target position, when a pressure toward the fixed part 10 is applied to the first movable part 20, the first movable part 20 is displaced toward the fixed part 10 by the pressure while the first elastic parts 31 of both ends are compressed, and when the pressure is released, the first elastic parts 31 are restored to an original uncompressed state by their own restoring force, thereby restoring the first movable part 20.

One or more second electrodes 21 are disposed on a side of the first movable member 20 facing the fixed member 10, and the second electrodes 21 may be strip-shaped electrodes or columnar electrodes, one end of which is fixed to the first movable member 20 and the other end of which extends toward a direction close to the fixed member 10, for example, may extend toward a side close to the fixed member 10 in a second direction perpendicular to the surface of the first movable member 20.

In the detecting device according to the embodiment of the present invention, the fixed part 10 and the first movable part 20 may be disposed opposite and parallel to each other, and the second direction may be parallel to the first direction, that is, the first electrode 11 and the second electrode 21 are parallel to each other. In the embodiment of the present invention, the planes of the free end surfaces of the first electrode 11 and the second electrode 21 may coincide with each other, that is, the lower end portions of the first electrode and the second electrode 21 do not face each other in the case where no pressure is applied to the first movable element 20; or the lower ends of the first electrode 11 and the second electrode 21 may face each other without applying pressure on the first movable part 20, forming one or more pairs of interdigital electrodes.

When no pressure is applied to the first movable member 20, the length of the finger portion between the first electrode 11 and the second electrode 21 may be zero or a predetermined length. As the pressure acting on the first movable member 20 toward the fixed member 10 increases, the first movable member 20 is gradually displaced toward the side closer to the fixed member 10, the distance between the first movable member 20 and the fixed member 10 gradually decreases, and the length of the interdigital portion between the first electrode 11 and the second electrode 21 gradually increases from zero or a predetermined length, so that the capacitance generated by the interdigital electrode changes according to the change in the distance between the first movable member 20 and the fixed member 10, and the change in the distance between the first movable member 20 and the fixed member 10 can be detected by monitoring the change in the capacitance of the interdigital electrode.

The calculation formula of the capacitance Cx generated by the finger insertion part electrode is as follows:

cx ═ epsilon S/4 pi kd formula 1

Where ε is the conductivity of the fill material between the electrodes, S is the area of the interdigitated fingers, k is the electrostatic force constant, and d is the spacing between the interdigitated fingers.

The circuit for detecting the capacitance variation amount may be implemented as an operational amplifier circuit shown in fig. 2, for example. As shown in fig. 2, Cx is a capacitance formed by the finger insertion portion electrode, the input terminal of the operational amplifier inputs the voltage U through the capacitance C, and the output terminal of the operational amplifier outputs the voltage U0, so that the variation of Cx can be calculated according to the following formula:

Cx-CxU/U0 formula 2

Assuming that the width of the finger-inserting portion electrode is L0, when the variation amount of the distance between the first movable member 20 and the fixed member 10 is Δ L, the increase amount of the area of the finger-inserting portion electrode is:

Δ S ═ Δ lxl 0 formula 3

Since the other parameters except the area S in the capacitance calculation formula 1 are all constants, the variation Δ Cx of the capacitance Cx is proportional to the variation Δ S of the area S, and the distance variation Δ L can be calculated by determining the area variation from the measured capacitance variation. The amount of change Δ L in the pitch further corresponds to the amount of elastic deformation of the first elastic member 31, and the magnitude of the pressure acting on the first movable member 20 can be obtained by combining the elastic coefficient of the first elastic member 31.

Besides real-time calculation of the pressure, the mapping relation between the capacitance variation and the pressure can be measured in advance and stored as a mapping chart, so that the pressure can be determined directly through the measured capacitance variation.

The detection device provided by the embodiment of the invention can accurately detect the magnitude of the acting force acting on the detection device, further accurately judge the force application state of the object or the force application state of an operator, and can achieve a better effect in the aspect of improving the pressure detection precision.

Referring to fig. 2, 3 and 5, in some embodiments of the present invention, the sensing device may include a second movable member 40 in addition to the fixed member 10 and the first movable member 20 shown in fig. 1. The second movable member 40 may be fixed at one end or may be fixed at both ends. One or more third electrodes 41 may be provided on the second movable member 40 on a side facing the

first electrodes

11, 111 or the

second electrodes

21, 121, and the third electrodes 41 may be strip-shaped electrodes or planar electrodes, one end of which is fixed to the second movable member 40 and the other end of which extends in a direction approaching the

first electrodes

11, 111 or the

second electrodes

21, 121.

The third electrode 41 may constitute an area-variable type capacitor with the

first electrode

11, 111 or the second electrode 121 or a pitch-variable type capacitor with the first electrode 11 in some embodiments of the present invention for detecting another force different from the force acting on the first

movable part

20, 121.

The following describes embodiments of the detecting device having the second movable member 40.

Fig. 3 is a schematic structural diagram of a detection apparatus according to another embodiment of the present invention.

As shown in fig. 3, the sensing device includes a second movable member 40 in addition to the fixed member 10 and the first movable member 20 shown in fig. 1. The second movable part 40 extends in a third direction perpendicular to the first direction or the second direction (i.e., the extending direction of the first electrode 11 or the second electrode 21), and both ends of the second movable part 40 are fixedly connected. The connection may be such that, when the first elastic member 31 is a portion of the connection member connected between the fixed member 10 and the first movable member 20, both ends of the second movable member 40 may be connected to other portions of the connection member. Or both ends of the second movable member 40 are connected to another connecting member provided on the fixed member 10 regardless of whether the first elastic member 31 is a part or an entirety of the connecting member connected between the fixed member 10 and the first movable member.

In addition, in addition to the embodiment shown in fig. 3 in which both ends of the second movable member 40 are connected to the connecting member near the fixed member 10 among the connecting members at both ends of the first elastic member 31, the present invention may include an embodiment in which both ends of the second movable member 40 are connected to the connecting member near the movable member 20 among the connecting members at both ends of the first elastic member 31.

One or more third electrodes 41 are disposed on the second movable member 40 on a side facing the first electrode 11 or the second electrode 21, and the third electrodes 41 may be strip-shaped electrodes or planar electrodes, one end of which is fixed to the second movable member 40 and the other end of which extends in a direction approaching the first electrode 11 or the second electrode 21.

The second movable member 40 has the second elastic member 32 connected to each of both ends thereof, and when the second movable member 40 is applied with a force in a length direction thereof, the second movable member 40 is displaced toward one end thereof, thereby compressing the second elastic member 32 connected to the one end or stretching the second elastic member 32 connected to the other end.

As shown in fig. 3, the free end of the third electrode 41 extends toward a direction close to the first electrode 11, and the free end of the third electrode 41 may extend to be opposite to the side surface of the first electrode 11.

When the second movable part 40 is displaced toward one end thereof to compress the second elastic part 32 connected to the one end, the third electrode 41 disposed on the second movable part 40 is driven to be displaced toward a direction approaching the first electrode 11 or away from the first electrode 11, and thus, the third electrode 41 on the second movable part 40 configured as above constitutes a variable pitch type capacitor with the first electrode 11.

In the embodiment shown in fig. 3, the area S of the capacitance formed by the third electrode 41 and the first electrode 11 facing each other between the electrodes is constant, and the capacitance varies inversely with the variation in the electrode pitch according to equation 1. Assuming that the distance variation between the third electrode 41 and the first electrode 11 is Δ d, the distance variation Δ d can be calculated according to equation 1 after the capacitance variation Δ Cx is measured according to the operational amplifier circuit shown in fig. 2 and equation 2. The distance change Δ d further corresponds to the amount of elastic deformation of the second elastic member 32, and the magnitude of the acting force acting in the longitudinal direction of the second movable member 40 can be obtained by combining the elastic coefficient of the second elastic member 32.

The embodiment of the invention fully utilizes the interaction among the electrodes through the same detection device, can realize the detection of different acting forces acting on the detection device by fewer parts and has good force measuring effect.

Fig. 4 is a schematic structural diagram of a detection apparatus according to still another embodiment of the invention.

The embodiment shown in fig. 4 differs from the embodiment shown in fig. 3 in the way in which the third electrode 41 is arranged. As shown in fig. 4, the third electrode 41 is disposed at a distance from the first electrode 11, and when the second movable member 40 is displaced toward one end thereof to compress the second elastic member 32 connected to the one end, the third electrode 41 disposed on the second movable member 40 is displaced toward a direction in which the facing area with the first electrode 11 becomes larger or the facing area with the first electrode 11 becomes smaller, and thus the third electrode 41 on the second movable member 40 configured as above constitutes a variable area type capacitor with the first electrode 11.

In the embodiment shown in fig. 4, the distance d between the third electrode 41 and the first electrode 11 is constant, and the capacitance varies inversely with the facing area of the electrodes according to equation 1. Assuming that the facing area variation between the third electrode 41 and the first electrode 11 is Δ S, after the capacitance variation Δ Cx is measured according to the operational amplifier circuit shown in fig. 2 and equation 2, the facing area variation Δ S can be calculated according to equation 1, and the shift amount of the second movable member 40 can be calculated according to the length of the third electrode 41. The amount of displacement further corresponds to the amount of elastic deformation of the second elastic member 32, and the magnitude of the urging force acting in the longitudinal direction of the second movable member 40 can be known in conjunction with the elastic coefficient of the second elastic member 32.

FIG. 5 is a schematic structural diagram of a detecting device according to an embodiment of the present invention in one state; fig. 6 is a schematic structural view of the detecting device shown in fig. 5 in another state.

In the detecting device in fig. 5, the fixed component 110, the first electrode 111, the first movable component 120 and the second electrode 121 are the same as the fixed component 10, the first electrode 11, the first movable component 20 and the second electrode 21 in the embodiment shown in fig. 1, and it should be noted that the elastic component (corresponding to the first elastic component 31 in the embodiment shown in fig. 1) connected between the fixed component 110 and the movable component 120 is omitted in fig. 5 for simplicity of illustration.

As shown in fig. 5, the second movable part 140 is disposed at one end side of the fixed part 110 and the first movable part 120 facing and disposed in parallel with each other, and extends in a fourth direction parallel to the first direction or the second direction (i.e., the extending direction of the first electrode 111 or the second electrode 121). One end of the second movable member 140 is fixed by, for example, an elastic member that can be elastically deformed in the circumferential direction. When a force is applied to the second movable part 140 to approach the first electrode 111 or the second electrode 121, the second movable part 140 rotates by a certain angle θ about its fixed end, so that the facing area with the first electrode 111 or the second electrode 121 changes, so that the third electrode 141 and the first electrode 111 or the second electrode 121 constitute a variable area type capacitor, as shown in fig. 7. It should be noted that the facing positions between the electrodes shown in fig. 7 are only exemplary, and the facing positions may be determined as needed in practical applications.

The relation between the capacitance change and the rotation angle theta can be obtained in advance through calculation, and the magnitude of the acting force can be determined according to the relation between the rotation angle theta and the acting force. As shown in fig. 7, assuming that the width of the second electrodes 121 is w, the distance between the second electrodes 121 is w1, and the sides of the third electrodes 141 are a and b, the facing area between the third electrode 141 and the one second electrode 121 closest to the third electrode 141 is:

s ═ a × b × sin θ formula 4

Meanwhile, the relation between the capacitance variation and the area variation can be determined according to the formula 1, the relation between the capacitance variation and the corner variation can be further determined, then the relation between the corner variation and the acting force is determined according to the elastic torsion coefficient of the elastic component at the fixed end of the second movable component, and finally the magnitude of the acting force is obtained.

In the embodiment of the present invention, when the variable area capacitor is formed between the third electrode and the first electrode or the second electrode, in order to reduce a distance error between the third electrode and the first electrode or the second electrode, an insulating layer 150 may be disposed between the

third electrode

41, 141 and the

first electrode

11, 111 or the

second electrode

21, 121, as shown in fig. 7.

Fig. 8 is a schematic layout view of the detecting device applied to the steering wheel according to the embodiment of the present invention.

As shown in fig. 8, the detecting device of the present invention shown in fig. 1 to 7 can be applied to a steering wheel of a vehicle, for example, installed in a both-hand grip position of the steering wheel. The installation mode is as follows: the detection device is arranged on the periphery of the steering wheel, and the fixing surface of the fixing

part

10, 110 of the detection device is fixed at the target position of the steering wheel, so that the detection device of the embodiment of the invention can be just contacted when a driver holds the steering wheel by hands, and the holding force of palms and the tight degree of the palms can be detected.

FIG. 9 is a schematic block diagram of a fatigue detection system in accordance with an embodiment of the present invention.

As shown in fig. 9, the fatigue detecting system according to the embodiment of the present invention includes a detecting device 1, a driving device 2, and a processing device 3.

The detecting device 1 includes any one of the detecting devices according to the embodiments of the present invention described above, and is mounted to a steering wheel of a vehicle as shown in fig. 8. The detection device 1 may also comprise a capacitive detection circuit as shown in fig. 2.

The driving device 2 is configured to supply an electrode driving signal to the detection device 1 based on a predetermined driving instruction. When the detecting device 1 is the detecting device including the second movable part according to the embodiment of the present invention, since the capacitors are formed between the first electrode and the second electrode and between the third electrode and the first electrode or the second electrode, the driving device 2 cannot supply power to all the electrodes at the same time when detecting capacitance, and may allocate one detection period T to two driving signals, perform control using a clock signal, apply one driving signal to the capacitor formed by the first electrode and the second electrode during T × D, and apply the other driving signal to the capacitor formed by the third electrode and the first electrode or the second electrode during T × (1-D).

The processing device 3 calculates the force acting on the detection device from the detection signal received from the detection device 1.

The fatigue detection system can accurately detect the acting force applied to the steering wheel by the driver, and is beneficial to detecting the fatigue state of the operator.

Fig. 10 is a schematic block diagram of a fatigue detection system according to another embodiment of the present invention.

As shown in fig. 10, the fatigue detection system of the embodiment of the invention further includes a reminding device 4, and the processing device 3 is configured to compare the calculated force with a predetermined threshold range, and send an indication signal to the reminding device 4 when the comparison result is that the calculated force exceeds the threshold range, and the reminding device 4 sends out an audible and visual reminding signal or an intelligent reminding voice when receiving the indication signal. For example, when the calculated force is small, it is determined that the driver is tired or does not hold the steering wheel, and corresponding reminding can be performed; and when the calculated force is larger, judging that the driver is tense or enters a drowsiness state, and carrying out corresponding reminding.

As shown in fig. 11, the fatigue detection system of the embodiment of the present invention may further include a heart rate sensor 5, which may be installed on a side of the detection device away from the steering wheel, or may be installed on the steering wheel near the detection device. In addition to the heart rate sensor 5, the fatigue detection system of the embodiment of the present invention may further include a temperature sensor (not shown), which may also be installed on a side of the detection device away from the steering wheel or on a position of the steering wheel close to the detection device. The fatigue detection system provided by the embodiment of the invention can comprehensively detect various physiological states of the driver, is favorable for accurately judging the current state of the driver, and can be used for effectively detecting fatigue.

While the embodiments of the present invention have been described above, the present invention is not limited to the above specific embodiments, and those skilled in the art can make various modifications or changes to the above embodiments without departing from the scope of the present invention, and these modifications and changes fall within the scope of the present invention as claimed.

Claims

1. A detection device, comprising:

a fixing member fixedly attached to a target position; at least one first electrode having one end fixed to the fixed member and the other end extending toward the first movable member in a first direction;

the first movable part is arranged opposite to and parallel to the fixed part and movably connected to the fixed part through a first elastic part;

at least one second electrode, one end of the second electrode is fixed on the first movable part, the other end of the second electrode extends towards the fixed part along a second direction, and the second direction is parallel to the first direction;

further comprising:

a second movable member having at least one end fixed;

at least one third electrode secured to the second movable element.

2. The detection device according to claim 1, wherein the third electrode and the first electrode or the second electrode constitute a variable area capacitor.

3. The detection apparatus according to claim 1, wherein an insulating layer is provided between the third electrode and the first electrode or the second electrode.

4. The detecting device according to claim 3, wherein the third electrode and the first electrode constitute a variable pitch type capacitor.

5. The detection apparatus according to any one of claims 2-4, wherein the second movable member extends in a third direction perpendicular to the first direction.

6. The detecting device according to claim 5, wherein the second elastic member is connected to each of both ends of the second movable member.

7. A testing device according to claim 1 or 2 wherein the second moveable member extends in a fourth direction parallel to the first direction.

8. A fatigue detection system, comprising: the detection apparatus of any one of claims 1-4; which is mounted to a vehicle steering wheel;

a drive device that supplies an electrode drive signal to the detection device based on a predetermined drive instruction;

and a processing device which calculates the force acting on the detection device based on the detection signal received from the detection device, and determines the current fatigue state of the operator.

9. The fatigue detection system of claim 8, wherein the processing device is further configured to compare the calculated force to a predetermined threshold range, and the system further comprises: and a reminder device that issues a reminder signal when the processing device determines that the calculated force is outside a predetermined threshold range.

10. The fatigue detection system of claim 8 or 9, further comprising:

a temperature sensor mounted on a side of the detection device away from the steering wheel or on the steering wheel adjacent the detection device; and/or

A heart rate sensor mounted on a side of the detection device away from the steering wheel or on the steering wheel adjacent the detection device.